Composite light source

ABSTRACT

A composite lamp having relatively high efficacy and improved color richness and warmth. The lamp is comprised of a mercury or a metal halide lamp and a tungsten halogen lamp which are located in a common housing. The mercury or metal halide lamp is of relatively high efficacy and relatively high lumen output whereas the tungsten halogen lamp is of relatively lower efficacy and lower lumen output and is used primarily to improve the warmth and richness of the light output of the composite lamp. The tungsten halogen lamp is mounted directly beneath the mercury lamp and is physically much smaller so that only a minimal amount of the lumen output of the mercury lamp is obscured.

United States Patent [1 1 Gruen 1 1 Dec. 30, 1975 1 1 COMPOSITE LIGHTSOURCE [75] Inventor: William Gruen, Encino, Calif.

[73] Assignee: William Gruen, Encino, Calif.

[22] Filed: July 22, 1974 [21] Appl. No.: 490,470

Primary ExaminerRichard M. Sheer Assistant Examiner-E. M. OConnorAttorney, Agent, or Firm-Browne, Beveridge, Degrandi & Kline 57 ABSTRACTA composite lamp having relatively high efficacy and improved colorrichness and warmth The lamp is comprised of a mercury or a metal halidelamp and a tungsten halogen lamp which are located in a common housing.The mercury or metal halide lamp is of relatively high efficacy andrelatively high lumen output whereas the tungsten halogen lamp is ofrelatively lower efficacy and lower lumen output and is used primarilyto improve the warmth and richness of the light output of the compositelamp. The tungsten halogen lamp is mounted directly beneath the mercurylamp and is physically much smaller so that only a minimal amount of thelumen output of the mercury lamp is obscured.

2 Claims, 2 Drawing Figures U.S. Patent Dec. 30, 1975 3,930,148

COMPOSITE LIGHT SOURCE The present invention relates to a compositelight source having an output of improved color richness and warmth andwhich appears to render objects illuminated with a sculptured or threedimensional quality.

Color richness is extremely important in many modern illuminationapplications such as in the illumination of goods or of an advertisingdisplay in a store. The warmth and richness of the light used mayfrequently determine the appeal which the goods on display will have tocustomers.

The richness and rendition of prior art light sources has not provensuitable for many applications. For instance it has been known in theprior art to utilize incandescent and fluorescent lamps in a commonhousing, but partly because of the light spread inherent in linearfluorescent sources the quality of the light emitted has not beensatisfactory. Further, the light output of many widely used highefficacyhigh lumen output light sources such as mercury or metal halidelamps has proven to be too flat or cool for effective displayillumination which requires warm light for effective viewing. On theother hand available light sources such as tung' sten halogen sourceswhich provide suitably warm and rich light from a color point of vieware inherently low efficacy sources having a low lumen output per wattand are therefore too expensive for many commercial applicationsrequiring extensive lighting.

It is thus an object of the present invention to provide a compositelight source having a relatively high efficacy but also having improvedcolor richness and warmth.

It is a further object of the invention to provide a composite lightsource including a supplementary lamp which will re-lightinstantaneously after power has been re-applied following a powerfailure.

As indicated above high efficacy lamps such as mercury or metal halidelamps provide a light which is too cool for many illuminationapplications whereas other lamps while providing light of suitablewarmth are too low in efficacy to operate economically. According to theinvention a light source having both high efficacy andsuitable warmth isprovided by utilizing a high lumen output mercury or metal halide lampand a lower lumen output tungsten halogen lamp in a common housing. Thesource is of relatively high efficacy because most of the light outputcomes from the mercury or metal halide lamp but provides suitable warmthand color rendition because the light from the tungsten halogen lampenriches the light emitted from the mercury lamp. The light emitted bythe composite light source is of a very special quality and appears togive objects illuminated therewith a sculptured or three dimensionaleffect. The tungsten halogen lamp is mounted directly below the mercurylamp and is particularly well suited because its small size ensures thatonly a minimal amount of the light output of the mercury lamp isblocked. The lumen output of the tungsten halogen lamp is adjustable tocontrol the degree of color richness of the composite source.

The invention will be better understood by referring to the accompanyingdrawings in which:

FIG. 1 is a sectional view of the improved light source of theinvention.

FIG. 2 is a partly open perspective view of the light source.

The primary lamp 1 of the composite light source is of the highintensity discharge type and may be either a mercury or a metal halidetype lamp. As discussed above it has been found that a mercury or metalhalide lamp by itself does not provide suitable color richness for manycommercial applications and therefore according to the invention thelight emitted by lamp is supplemented by light emitted from lamp 2. Lamp2 is a tungsten halogen lamp which is quite small in physical size, sothat it obscures only a small portion of the light emitted from lamp 1.

According to the invention lamps l and 2 are both mounted in housing 5with lamp 2 being disposed directly beneath lamp 1. Housing 5 may assumea variety of shapes and may for instance be square, round, circular, orrectangular, the circular embodiment shown in FIGS. 1 and 2 beingillustrative only. Additionally, the fixture 5 may be mounted in avariety of ways as is known to those skilled in the art.

Member 3 is a reflector for the light emitted from lamp 1 and in thecircular embodiment shown takes the form of a portion of a cone. Member3 may for instance be made of metal and is polished on its insidesurface to reflect the emitted light.

Support bar 6 runs across the center of the housing beneath lamp 1 andif desired may be a hollow tube along which electrical conductors tolamp 2 are run. It is not necessary for support bar 6 to extend all theway across the housing as shown. In the preferred embodiment lamp 2 istubular in shape as shown and is mounted in reflector 9 which may be anelliptical, parabolic or spherical reflector. Reflector 9 with lamp 2therein is mounted on support bar 6 via mounting means 8 which may beany conventional clamping means.

The electrical components associated with the lamps may be housed in thecompartment formed between a wall of housing 5 and reflector 3.Capacitor l1 and ballast l2 necessary for the operation of mercury lamp1 are shown strapped to the housing wall by straps l5 and 16. A voltagecontrol device 13 such as a rheostat or a solid state voltage controldevice is shown mounted on reflector 3. This device is connected in thevoltage supply circuit to tungsten halogen lamp 2 and control knob 14 isadjustable to supply a desired voltage to lamp 2. lf it is desired tocontrol the voltage to lamp 2 remotely then device 13 as well as theother electrical components may be located outside of and remotely fromthe housing 5. The connections between components 11, 12, and 13 andlamps l and 2 are conventional and have not been shown in the drawings.

The amount of color richness or warmth of the composite light source maybe controlled by adjusting knob 14. Thus in different applications itmay be desired to bring out different colors in varying amounts and thiscan be achieved by adjustment of the knob 14 which controls the lumenoutput of lamp 2. Thus the color rendition of the lamp may be modulatedto suit a particular application.

The diffuser 7 may be metallic or plastic and to prevent light lossdirectly below tungsten halogen lamp 2 diffuser 7 has a central hole 10therein.

Mercury lamp 1 has alifetime of approximately 24,000 hours. The lifetimeof the tungsten halogen lamp if it were run at rated voltage would bemany times less than this. However a relatively small decrease in theoperating voltage of this lamp results in a large increase in lifetime.It has been found that running a tungsten halogen lamp which is rated at120 volts at between 95 to 100 volts increases the lamps lifetimebetween and times. Thus by proper choice of operating voltage thelifetime of the tungsten halogen lamp may be made substantially equal tothe life of the mercury lamp. Additionally, a characteristic of tungstenhalogen lamps which results from the halogen cycle principle on whichthe lamps work is that they do not blacken and therefore maintain theirinitial light output throughout life. Since the lumen output of themercury lamp decreases with age an additional function of voltagecontrol device 13 is that it can be adjusted so that the relative lightoutputs of lamps 1 and 2 are maintained at a desired value as the lampsSpecific lamps are chosen according to the invention so that the lumenoutput of the higher efficacy'mercury or metal halide lamp issubstantially greater than the lumen output of the lower efflcacytungsten halogen lamp. While it will be apparent to those skilled in theart that many different specific lamp wattages and shapes may be usedwithout departing from the scope of the invention in a preferredembodiment a 175 watt mercury lamp denoted as BT 28 having a mogul basewasused. This lamp is eight and one-half inches long and thre e andone-half inches in diameter at its widest part. A tubular tungstenhalogen lamp denoted as T4 was used and this lamp is three and one-halfinches long and one-half inch in diameter. Hence it is seen that thedimensions of the tungsten halogen lamp are quite small compared tothose of the mercury lamp. The 175 watt mercury lamp emits approximately7,000 lumens of light while the 300 watt quartz halogen lamp which isinherently a lower efficacy lamp than the mercury lamp emitsapproximately 2,500 lumens when operated at between 95 and 100 volts.

The light resulting from the particular combination of lamps isobservedto be of a special quality having improved color rendition andrichness and giving illuminated objectsa sculptured effect. i 1

Further, the composite light source has the capability of. being able tore-light instantaneously-when power is re-applied after a power failureor when turned on at the beginning of the day. Thus while mercury lamp 1will always take four or five minutes after power is applied for the arcto strike the tungsten halogen lamp will light instantaneously and thusprovide illumination sooner than if the mercury lamp were used byitself.

While I have disclosed and described the preferred embodiments of myinvention, I wish it understood that I do not intend to be restrictedsolely thereto, but that I do intend to include all embodiments thereofwhich would be apparent to one skilled in the art and which come withinthe spirit and scope of my invention.

What is claimed is: r

l. A color modulatable composite light source comprising a mercury lampand an inherently lower efficacy tungsten halogen lamp having a ratedvoltage, a housing in which said lamps are enclosed and which includesat least a reflector for reflecting the light emitted by's'aid lamps,said tungsten halogen lamp being mounted in said housing directlybeneath said mercury lamp and being substantially smaller in physicalsize than said mercury lamp so that it obscures only a minimal amount ofthe lumen output of said mercury lamp, means for simulteneouslysupplying electrical energy to said lamps in respective'amounts to causesaid mercury lamp to have a substantially greater lumen output than saidtungsten halogen lamp, and color modulator means comprising a manuallyoperable means for varying the amount of electrical energy fed to saidtungsten halogen lamp to vary the color output of the light source. I i

2. A color modulatable composite light source comprising a metal halidelamp and an inherently lower efflcacy tungsten halogen lamp having arated voltage, a housing in which said lamps are enclosed and whichincludes at least a reflector for reflecting the light emitted by saidlamps, said tungsten halogen lamp being mounted in said housing directlybeneath said metal halide lamp and being substantially smaller'inphysical size than said metal halide lamp so that it obscures only aminimal amount of the lumen output of said metal halide lamp, means forsimultaneously supplying electrical energy to said lamps in respectiveamounts to cause said metal halide lamp to have a substantially greaterlumen output than said tungsten halogen lamp, and color modulator meanscomprising a manually operable means for varying the amount ofelectrical energy fed to said tungsten halogen lamp to vary the coloroutput of the light source.

1. A COLOR MODULATABLE COMPOSITE LIGHT SOURCE COMPRISING A MERCURY LAMPAND AN INHERENTLY LOWER EFFICACY TUNGSTEN HALOGEN LAMP HAVING A RATEDBOLTAGE, A HOUSING IN WHICH SAID LAMPS ARE ENCLOSED AND WHICH INCLUDESAT LEAST A REFLECTOR FOR REFLECTING THE LIGHT EMITTED BY SAID LAMPS,SAID TUGSTEN HALOGEN LAMP BEING MOUNTED IN SAID HOUSING DIRECTLY BENEATHSAID MERCURY LAMP AND BEING SUBSTANTIALLY SMALLER IN PHYSICAL SIZE THANSAID MERCURY LAMP SO THAT ITS OBSCURES ONLY A MINIMAL AMOUNT OF THELUMEN OUTPUT OF SAID MERCURY LAMP, MEANS FOR SIMULTENEOUSLY SUPPLYINGELECTRICAL ENERGY TO SAID LAMPS IN RESPECTIVE AMOUNTS TO CAUSE SAIDMERCURY LAMP TO HAVE A SUBSTANTIALLY GREATER LUMEN OUTPUT THAN SAIDTUNGSTEN HALOGEN LAMP, AND COLOR MODULATOR MEANS COMPRISING A MANUALLYOPERABLE MEANS FOR VARYING THE AMOUNT OF ELECTRICAL ENERGY FED TO SAIDTUNGSTEN HALOGEN LAMP TO VARY THE COLOR OUTPUT OF THE LIGHT SOURCE.
 2. Acolor modulatable composite light source comprising a metal halide lampand an inhereNtly lower efficacy tungsten halogen lamp having a ratedvoltage, a housing in which said lamps are enclosed and which includesat least a reflector for reflecting the light emitted by said lamps,said tungsten halogen lamp being mounted in said housing directlybeneath said metal halide lamp and being substantially smaller inphysical size than said metal halide lamp so that it obscures only aminimal amount of the lumen output of said metal halide lamp, means forsimultaneously supplying electrical energy to said lamps in respectiveamounts to cause said metal halide lamp to have a substantially greaterlumen output than said tungsten halogen lamp, and color modulator meanscomprising a manually operable means for varying the amount ofelectrical energy fed to said tungsten halogen lamp to vary the coloroutput of the light source.